WO2011155091A1

WO2011155091A1 - Two-needle sewing machine and two-needle sewing machine stitch forming method

Info

Publication number: WO2011155091A1
Application number: PCT/JP2010/073504
Authority: WO
Inventors: 英夫麻生; 修宏西
Original assignee: ミドリ安全株式会社; 株式会社ミドリ安全縫技研究所
Priority date: 2010-06-10
Filing date: 2010-12-27
Publication date: 2011-12-15
Also published as: CN102933759B; CN102933759A; EP2581481B1; TW201144511A; BR112012031468A2; JP2011255026A; US20130081563A1; US8978565B2; EP2581481A1; MX2012014122A; TWI509125B; BR112012031468B1; RU2508424C1; MX336843B; JP5389741B2; EP2581481A4

Abstract

Disclosed is a two-needle sewing machine that improves strength in a convex curve part by bringing a pair of stitches close together when sewing an item to be sewed that comprises the convex curve part. A two-needle sewing machine (1) comprises a bed part (3); a column part (5); an arm part (6); a needle shaft (11) that is disposed on the leading part of the arm part (6); two sewing needles (13, 14) that are attached to the needle shaft (11); two horizontal rotary hooks (15, 16) that catch the respective needle thread loops of the two sewing needles (13, 14); and a conveyor member (21) that conveys a material to be sewed (40) in a direction approximately orthogonal to the bed part (3). On the two-needle sewing machine (1), the sewing needle (13), which is positioned in a location further from the column part (5), is disposed closer to the conveyance side of the material to be sewed (40) than the sewing needle (14) that is positioned in a location closer to the column part (5).

Description

2-needle sewing machine and seam forming method of 2-needle sewing machine

The present invention relates to a two-needle sewing machine that forms two stitches on a workpiece such as cloth and leather by reciprocating two sewing needles, and a seam forming method using the two-needle sewing machine.

Conventionally, a two-needle sewing machine has been provided with a bed portion on which a workpiece such as cloth or leather is placed, a pedestal portion standing upward from one (right side) side of the bed portion, and an upper portion of the pedestal portion. And an arm portion provided substantially parallel to the bed portion. A needle bar that reciprocates in the vertical direction by a drive motor (not shown) is provided at the tip (left) of the arm. Two sewing needles are attached to the needle bar. The bed portion has two horizontal hooks that respectively hook the loops of the needle threads of the two sewing needles, and a feeding member that feeds a material to be sewn such as cloth or leather in a direction substantially perpendicular to the bed portion. ing.

This conventional two-needle sewing machine is formed by two stitches in close contact with two stitches. As shown in FIG. 26, the two

sewing needles

91 and 92 are arranged at a predetermined interval in the feed direction T of the sewing object 30 and formed by the sewing needle 91 for the purpose of obtaining strong sewing. The seam 95A to be formed is in close contact with the seam 96A formed by the sewing needle 92 (for example, Patent Documents 1 and 2).

Japanese Utility Model Publication No. 52-10527 Japanese Patent No. 4456846

The above-described two-needle sewing machine intermittently sends the workpiece 30 forward by the feeding member, but performs sewing while holding the workpiece 30 with both hands. In the two-needle sewing machine, when the workpiece 30 is sewed linearly in the feed direction T, as shown in FIG. 26, two

seams

95A and 96A are formed in close contact with each other. As shown in FIG. 2, when the sewing product 30 is rotated with respect to the feed direction T of the feed member in accordance with the shape and sewn, the two

seams

95B and 96B are formed apart from each other. That is, the two-needle sewing machine, when the sewing product 30 is rotated in the feeding direction T of the feed member and the sewing product 30 is curvedly sewn, a pair of sewings in a direction substantially perpendicular to the sewing direction P5. The distance between the

needles

91 and 92 is widened to form a pair of spaced

seams

95B and 96B. Therefore, the conventional two-needle sewing machine has a problem in that, in the case of curve stitching, the width of the pair of seams is widened, so that it is not the purpose of obtaining a strong sewing by bringing the pair of seams into close contact with each other. .

As shown in FIG. 28, when the sewing product 40 having the

convex portions

46 and 48 is sewn by the above-described conventional two-needle sewing machine, the

linear portions

41 and 45 form a pair of

tight stitches

95A and 96A. However, the

curved portions

42 and 44 of the

convex portions

46 and 48 form a pair of spaced

seams

95B and 96B. The sewing product 40 is usually formed in a bag shape, and the padding is accommodated therein, but when it is accommodated, the force applied to the

convex portions

46 and 48 is large. It is desired to strengthen the sewing of 44. However, when the

curved portions

42 and 44 are sewed by the above-described two-needle sewing machine, the

stitches

95B and 96B are separated from each other, so that the strength of the sewing is insufficient, and the pair of

stitches

95B and 96B is easy to cut, and the stuffing is It will jump out. Therefore, in the conventional two-needle sewing machine, when the sewing product 40 having the

convex portions

46 and 48 is sewn, the widths of the

seams

95B and 96B for sewing the peripheral edges of the

convex portions

46 and 48 are widened and the strength is insufficient. In addition, there is a problem of forming a sewing product having poor durability. In particular, when sewing a leather seat of a car seat, strong sewing is desired from the viewpoint of safety and appearance. However, since there are many curvilinear sewings, a pair of seams are separated and weakened. The force applied to the leather seat of a car seat is much greater than the leather seat of a normal chair, so a pair of seams break or expand, and some of the pads such as urethane foam packed inside pop out. There is a problem that it protrudes and the safety and appearance are impaired.

The present invention has been devised in view of the above problems, and when sewing a bag-like sewing product, when sewing a convex curve portion that requires strength, a pair of seams are brought close to each other. An object of the present invention is to provide a two-needle sewing machine capable of improving strength and a method of forming a seam of a two-needle sewing machine.

In order to achieve the above object, a two-needle sewing machine according to claim 1 of the present application has a bed portion on which a workpiece is placed, a pedestal portion erected upward from one side of the bed portion, and a pedestal portion. An arm part provided substantially parallel to the bed part from the upper part of the needle, a needle bar provided at the front part of the arm part and reciprocating in the vertical direction by a drive motor, and two sewing needles attached to the needle bar, Two needles provided on the bed portion, each having two horizontal hooks for hooking loops of needle threads of the two sewing needles, and a feed member for feeding the sewing product in a direction substantially perpendicular to the bed portion. Sewing needles, which are sewing machines that are arranged on both sides in a direction substantially perpendicular to the feed direction of the sewing product, and that are arranged at positions close to the pedestal portion. Further, it is provided on the feed side of the workpiece.

In order to achieve the above object, a method for forming a seam of a two-needle sewing machine according to claim 2 of the present application includes a bed portion on which a workpiece is placed, and a pedestal portion erected upward from one side of the bed portion. , An arm part provided substantially parallel to the bed part from the upper part of the pedestal part, a needle bar provided at the tip part of the arm part and reciprocating vertically by a drive motor, and two attached to the needle bar Sewing needles, two horizontal hooks provided on the bed portion and hooking loops of needle threads of the two sewing needles, respectively, and a feed member for feeding the workpiece in a direction substantially perpendicular to the bed portion Sewing needles are arranged on both sides substantially perpendicular to the feed direction of the work to be sewn, and the sewing needles arranged at a position distant from the pedestal portion are covered by sewing needles arranged at a position close to the pedestal portion. This is a method for forming a seam of a two-needle sewing machine provided on the feed side of the sewing product. The pair of sewing needles form a pair of stitches having a normal stitch width by feeding the workpiece in the feeding direction of the feeding member, and the workpiece is separated from the pedestal portion with respect to the feeding direction of the feeding member. A pair of stitches having a stitch width narrower than a normal stitch width is formed by a pair of sewing needles by feeding in the direction.

In order to achieve the above-described object, a method for forming a seam of a two-needle sewing machine according to claim 3 of the present application includes a bed portion on which a workpiece is placed, and a pedestal portion erected upward from one side of the bed portion. , An arm part provided substantially parallel to the bed part from the upper part of the pedestal part, a needle bar provided at the tip part of the arm part and reciprocating vertically by a drive motor, and two attached to the needle bar Sewing needles, two horizontal hooks provided on the bed portion and hooking loops of needle threads of the two sewing needles, respectively, and a feed member for feeding the workpiece in a direction substantially perpendicular to the bed portion Sewing needles are arranged on both sides substantially perpendicular to the feed direction of the work to be sewn, and the sewing needles arranged at a position distant from the pedestal portion are covered by sewing needles arranged at a position close to the pedestal portion. A two-needle sewing machine provided on the feed side of the sewing product is provided with a convex portion. A seam forming method for forming a seam at a peripheral edge of a product, wherein a pair of stitches having a normal seam width is formed by a pair of sewing needles by feeding the product to be sewn in the feed direction of the feed member, and sewing A pair of seams having a seam width narrower than a normal seam width is formed on the peripheral edge of the convex portion by a pair of sewing needles by feeding an object in a direction away from the pedestal with respect to the feed direction of the feed member. And

The two-needle sewing machine and the method for forming a seam of the two-needle sewing machine according to the present invention are such that the sewing side edge of the sewing object such as cloth or leather is directed to the pedestal part, and the sewing object is placed on the bed part. Therefore, the sewing can be performed smoothly without the article to be sewn contacting the pedestal. The two-needle sewing machine and the method for forming the stitches of the two-needle sewing machine according to the present invention include a needle thread loop formed when the needle bar moves up and down when driven and a pair of sewing needles return through the workpiece. The sword tip of the horizontal hook hooks to perform the main sewing, and the feed member intermittently feeds the workpiece in the feed direction to form a pair of seams. The two-needle sewing machine and the method for forming a seam of the two-needle sewing machine according to the present invention are such that a sewing needle disposed at a position distant from the pedestal portion is more sewn than a sewing needle disposed at a position close to the pedestal portion. Since it is provided on the feed side, when the workpiece is fed substantially parallel to the feed direction, a pair of stitches having a normal stitch width is formed on the workpiece. When rotating in a direction away from the pedestal, the distance between the pair of sewing needles in a direction substantially perpendicular to the sewing direction becomes narrower, the seam width approaches zero as much as possible, and the pair of seams closely overlap each other. It becomes like this. As described above, the two-needle sewing machine and the stitch forming method of the two-needle sewing machine according to the present invention have an effect that the pair of stitches approach each other at the time of curve stitching and the strength of the stitches can be improved. Therefore, the two-needle sewing machine and the method for forming a seam of the two-needle sewing machine according to the invention of the present application are such that, when a bag-like sewing product is sewn, if the convex curve portion requires strength, the seam is brought closer to the strength. There is an effect that can be improved.

1 is an overall perspective view showing one embodiment of a two-needle sewing machine according to the present invention. It is principal part explanatory drawing of the 2-needle sewing machine of FIG. It is explanatory drawing which shows the normal stitch formation method of the 2 needle | hook sewing machine of FIG. It is explanatory drawing which shows the seam formation method which the 2 needle | hook sewing machine of FIG. 1 inclined. It is explanatory drawing which shows the seam formation method which the 2 needle | hook sewing machine of FIG. 1 inclined. It is explanatory drawing which shows the seam formation method which the 2 needle | hook sewing machine of FIG. 1 inclined. It is explanatory drawing of the to-be-sewn material sewn by the 2 needle | hook sewing machine of FIG. It is a perspective view of the to-be-sewn product sewn by the two-needle sewing machine of FIG. It is explanatory drawing which reversed the to-be-sewn material of FIG. FIG. 10 is an explanatory diagram of a main part of the sewing product in FIG. It is a perspective view which shows the 1st sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the 2nd sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the 3rd sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the 4th sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the 5th sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the 6th sewing procedure by the 2 needle | hook sewing machine of FIG. It is a perspective view which shows the specific example of a to-be-sewn material. FIG. 18 is a sectional view taken along the line dd in FIG. It is a whole perspective view which shows the other form of a 2 needle | hook sewing machine. It is principal part explanatory drawing of the 2 needle | hook sewing machine of FIG. FIG. 20 is an explanatory view showing a normal stitch forming method of the two-needle sewing machine of FIG. 19. FIG. 20 is an explanatory view showing a method of forming a seam inclined by the two-needle sewing machine of FIG. 19. FIG. 20 is an explanatory view showing a method of forming a seam inclined by the two-needle sewing machine of FIG. 19. FIG. 20 is an explanatory view showing a method of forming a seam inclined by the two-needle sewing machine of FIG. 19. It is explanatory drawing of the to-be-sewn material sewn by the two-needle sewing machine of FIG. It is explanatory drawing which shows the normal stitch formation method of the conventional 2 needle | hook sewing machine. It is explanatory drawing which shows the method of forming the seam which the conventional 2 needle | hook sewing machine inclined. It is explanatory drawing of the to-be-sewn material sewn by the conventional 2 needle | hook sewing machine.

As shown in FIG. 1, the two-needle sewing machine 1 includes a bed portion 3 on which a workpiece is placed, a leg column portion 5 erected upward from one side of the bed portion 3, and a leg column portion 5. An arm part 6 provided substantially parallel to the bed part 3 from the upper part, a needle bar 11 provided at the front part of the arm part 6 and reciprocating vertically by a drive motor, and two attached to the needle bar 11 Sewing needles 13 and 14, two

horizontal hooks

15 and 16 provided on the bed portion 3 for hooking loops of needle threads of the two

sewing needles

13 and 14, and a bed portion 3 And a feed member 21 for feeding in a substantially perpendicular direction. In the two-needle sewing machine 1, sewing needles 13 and 14 are arranged on both sides in a direction substantially perpendicular to the feed direction T of the workpiece, and the sewing needle 13 arranged at a position away from the leg column part 5 includes the leg column part 5. Is provided on the feed side of the sewing product from the sewing needle 14 arranged at a position close to the sewing machine.

As shown in FIG. 3, the above-described stitch forming method of the two-needle sewing machine 1 is such that the normal stitch width D1 is set by the pair of

sewing needles

13 and 14 by feeding the workpiece 30 in the feeding direction T of the feeding member 21. A pair of

stitches

31A, 32A provided is formed. Further, as shown in FIG. 6, the pair of

sewing needles

13 and 14 feeds the workpiece 30 in a direction away from the pedestal 5 with respect to the feeding direction T of the feeding member 21, so that it is narrower than the normal stitch width D1. A pair of

seams

31D and 32D having a seam width D4 are formed.

As shown in FIGS. 7 and 8, the seam forming method of the two-needle sewing machine 1 described above is a seam forming method of forming seams on the periphery of a bag-like sewing product 40 having

convex portions

46 and 48. A pair of

stitches

31A and 32A having a normal stitch width D1 are formed by the pair of

sewing needles

13 and 14 by feeding the workpiece 40 in the feeding direction of the feeding member 21. Further, by sending the workpiece 40 in a direction away from the pedestal 5 with respect to the feed direction T of the feed member 21, a pair of

sewing needles

13 and 14 are arranged on the periphery of the

convex portions

46 and 48 from the normal stitch width D1. A pair of

seams

31D and 32D having a narrow seam width D4 are formed.

As shown in FIG. 11, the two-needle sewing machine 1 has a sewing side end edge (right straight portion 41) of a sewing product 40 such as cloth, leather or the like facing the pedestal 5 and the sewing product 40 in a bed. Since it is placed on the portion 3, it is possible to sew smoothly without the sewing object 40 contacting the pedestal portion 5. When the two-needle sewing machine 1 is driven, the needle bar 11 moves up and down, and the loop of the needle thread formed when the pair of

sewing needles

13 and 14 return through the workpiece 40 is moved to the

horizontal hooks

15 and 16. The sword tip hooks to perform the main sewing, and the feed member 21 intermittently feeds the workpiece 40 in the feed direction T to form a pair of seams 31 and 32. In the two-needle sewing machine 1, the sewing needle 13 disposed at a position distant from the pedestal portion 5 is provided on the feed side of the workpiece 40 from the sewing needle 14 disposed at a position close to the pedestal portion 5. Therefore, when the workpiece 40 is fed substantially parallel to the feed direction T, as shown in FIG. 12, a pair of

stitches

31A and 32A having a normal stitch width D1 are formed on the workpiece 40. As shown in FIG. 13, when the workpiece 40 is rotated in the direction away from the pedestal 5 with respect to the feed direction T (left direction L), a pair of directions in a direction substantially perpendicular to the sewing direction P is obtained. As the interval between the sewing needles 13 and 14 becomes narrower, the seam width approaches zero as much as possible, and the pair of

seams

31D and 32D overlap closely. As described above, the two-needle sewing machine 1 can improve the strength of the seam when the pair of seams 31 and 32 approach each other at the time of curve sewing. Therefore, when sewing the bag-like sewing product 40 having the

convex portions

46 and 48, the two-needle sewing machine 1 is close to the seam in the convex

curved portions

42 and 44 that require strength. Strength can be improved.

Furthermore, the two-needle sewing machine will be described in detail. As shown in FIG. 1, a sewing machine body 2 of a two-needle sewing machine 1 is erected upward from a bed part 3 on which a material to be sewn such as cloth or leather is placed and from one (right side) side of the bed part 3. The pedestal column portion 5 and the arm portion 6 provided substantially parallel to the bed portion 3 from the upper portion of the pedestal column portion 5 are configured.

A needle bar 11 that is reciprocated in the vertical direction by a drive motor (not shown) is provided at the tip (left) of the arm 6. A needle retaining member 12 to which two

sewing needles

13 and 14 are attached is fixed to the lower end of the needle bar 11. In the bed portion 3, two

horizontal shuttles

15 and 16 that rotate in synchronization with the reciprocation of the needle bar 11 are provided. The horizontal hook 16 located on one side (right side) hooks the needle thread loop of the sewing needle 14 and the horizontal hook 15 located on the other side (left side) hooks the needle thread loop of the sewing needle 13. It is going to crawl.

In the bed portion 3, a lower feed member 21 is provided between the

horizontal hooks

15 and 16. The lower feed member 21 synchronizes with the reciprocating motion of the needle bar 11 and intermittently feeds a material to be sewn such as leather or cloth in a direction substantially perpendicular to the bed portion 3 (forward, T direction shown in FIG. 1). Configured to send.

The two-needle sewing machine 1 is formed by

sewing needles

13 and 14 so that two seams are formed substantially in parallel. The sewing needles 13 and 14 are separated from each other by about 3 mm or more due to the outer diameter of the sewing needle itself and the arrangement of the horizontal hook, etc. In order to make the width of the seam about 0.3 mm, The position of the other sewing needle 14 is shifted. The width of the seam of about 0.3 mm is a distance for preventing the seam formed by the sewing needle 13 and the seam formed by the sewing needle 14 from stepping on each other. As shown in FIG. 2, the two-needle sewing machine 1 has

sewing needles

13 and 14 arranged on both sides substantially perpendicular to the feed direction T of the workpiece, and is arranged at a position (left side) away from the pedestal 5. The sewing needle 13 is positioned forward (front side in the feed direction T), and the sewing needle 14 disposed at a position close to the pedestal 5 (right side) is located rearward (back side in the feed direction T). The sewing needle 13 is provided on the feed side of the sewing product from the sewing needle 14. Therefore, as shown in FIG. 3, although the interval between the sewing needles 13 and 14 is separated as described above, the interval between the sewing needles 13 and 14 in the direction substantially perpendicular to the sewing direction P1 is narrow, and the width of the stitches. Is made smaller.

A horizontal hook 15 that holds the loop of the needle thread formed by the sewing needle 13 and a horizontal hook 16 that holds the loop of the needle thread formed by the sewing needle 14 are arranged on both the left and right sides of the sewing needles 13 and 14. Yes. That is, the

horizontal hooks

15 and 16 are arranged on both sides substantially perpendicular to the feed direction T of the sewing product, and the horizontal hook 15 arranged at a position (on the left side) away from the pedestal 5 is forward (feed direction T). The horizontal hook 16 is located on the rear side (the rear side in the feed direction T) and is positioned on the rear side (the rear side in the feed direction T). It is provided on the material feed side.

As shown in FIG. 3, the two-needle sewing machine 1 sends a pair of

sewing needles

13, 13 by sending a workpiece 30 such as leather or cloth in a sewing direction P <b> 1 substantially parallel to the feed direction T of the lower feed member 21. 14, a pair of

seams

31A and 32A having a normal seam width D1 is formed. As shown in FIG. 4, the two-needle sewing machine 1 rotates the workpiece 30 counterclockwise in the sewing direction P2 (inclination angle of about 5 degrees) away from the pedestal 5 with respect to the feed direction T of the lower feed member 21. The distance between the sewing needles 13 and 14 in the direction substantially perpendicular to the sewing direction P2 is further reduced, and a pair of stitches having a stitch width D2 narrower than the normal stitch width D1 by the pair of

sewing needles

13 and 14 are provided. 31B and 32B are formed.

As shown in FIG. 5, the two-needle sewing machine 1 rotates the workpiece 30 counterclockwise in the sewing direction P3 (inclination angle of about 10 degrees) away from the pedestal 5 with respect to the feeding direction T of the lower feeding member 21. , The distance between the sewing needles 13 and 14 in a direction substantially perpendicular to the sewing direction P3 is further narrowed, and the pair of stitches 31C having a stitch width D3 narrower than the stitch width D2 by the pair of

sewing needles

13 and 14; 32C is formed. As shown in FIG. 6, the two-needle sewing machine 1 rotates the workpiece 30 counterclockwise in the sewing direction P4 (inclination angle of about 15 degrees) away from the pedestal 5 with respect to the feed direction T of the lower feed member 21. The distance between the sewing needles 13 and 14 in the direction substantially perpendicular to the sewing direction P4 is further reduced, and a pair of stitches 31D having a stitch width D4 narrower than the stitch width D3 by the pair of

sewing needles

13 and 14. 32D is formed. The

seams

31D and 32D are in a state of being closely overlapped with each other. Thus, the stitch width of the two-needle sewing machine 1 becomes narrower as the left rotation angle of the sewing object 30 is increased. In the two-needle sewing machine 1, when the left rotation angle of the sewing product 30 is further increased, the left seam 31 may move to the right and the right seam 32 may move to the left. However, the pair of seams 31 and 32 are in close contact with each other, so that a strong sewing can be obtained.

The above-described two-needle sewing machine 1 sews a bag-like sewing product 40 as shown in FIGS. The sewing product 40 is composed of a pair of

sheet members

40A and 40B such as cloth and leather. The

sheet members

40A and 40B have a curved right convex portion 46, a left convex portion 48, and a curved central concave portion 47. The

sheet members

40A and 40B include a substantially straight right straight portion 41, a left straight portion 45, a substantially semicircular convex right curved portion 42 continuous from the right straight portion 41, and a substantially semicircle continuous from the left straight portion 45. It consists of a convex left curved portion 44, a right curved portion 42, and a substantially semicircular concave central curved portion 43 continuous to the left curved portion 44. The right curved portion 42 forms a right convex portion 46, and the left curved portion A left convex portion 48 is formed by 44, and a central concave portion 47 is formed by the central curved portion 43.

As shown in FIG. 11, the two-needle sewing machine 1 performs sewing substantially in parallel along the right straight portion 41 of the sewing product 40 in which the pair of

sheets

40A and 40B are overlapped. As shown in FIG. 12, the two-needle sewing machine 1 sends the workpiece 40 in the sewing direction P1 substantially parallel to the feed direction T of the lower feed member 21, so that a normal stitch width is obtained by the pair of

sewing needles

13 and 14. A pair of

seams

31A and 32A provided with D1 are formed. As shown in FIG. 13, when the two-needle sewing machine 1 performs sewing along the right curved portion 42, the sewing machine 40 moves the workpiece 40 away from the pedestal portion 5 with respect to the feed direction T of the lower feed member 21 ( Since it is fed while being tilted in the left direction L), the width of the seam formed by the pair of

sewing needles

13 and 14 is reduced to substantially zero, and the pair of

seams

31D and 32D are in close contact with each other.

As shown in FIG. 14, when the two-needle sewing machine 1 performs the sewing from the right curved portion 42 along the central curved portion 43, the pedestal portion of the sewing object 40 with respect to the feeding direction T of the lower feeding member 21. Therefore, the distance between the pair of

seams

31E and 32E formed by the pair of

sewing needles

13 and 14 is a seam width D5 wider than the normal seam width D1. As shown in FIG. 15, when the two-needle sewing machine 1 performs sewing along the left curved portion 44 from the central curved portion 43, the pedestal portion of the sewing object 40 with respect to the feeding direction T of the lower feeding member 21. As described above, the pair of

seams

31D and 32D formed by the pair of

sewing needles

13 and 14 are in close contact with each other and are substantially overlapped with each other. As shown in FIG. 16, when the two-needle sewing machine 1 performs sewing along the left straight line portion 45 from the left curved portion 44, the pedestal portion of the sewing object 40 with respect to the feed direction T of the lower feed member 21. 5, the distance between the pair of

seams

31A and 32A formed by the pair of

sewing needles

13 and 14 becomes a normal seam width D1 (see FIG. 7).

As shown in FIGS. 7 and 8, the sewing product 40 includes stitches 31 </ b> D and 32 </ b> D that sew the peripheral edges of the right convex portion 46 and the left convex portion 48 closely overlap each other, and stitches 31 </ b> E that sew the peripheral edge of the central concave portion 47. The interval of 32E is expanded. The sewing product 40 has a large force applied to the

convex portions

46 and 48, but the

seams

31D and 32D are closely overlapped with each other, so the strength is improved, and the

seams

31D and 32D are difficult to expand and difficult to cut. Strong and strong. On the other hand, since the force to be applied to the concave portion 47 is small, there is no particular problem even if the widths of the

seams

31E and 32E are expanded.

As shown in FIGS. 9 and 10, the sewing product 40 is used by turning it upside down, with the seams 31A to 31E positioned on the outer edge, the seams 32A to 32E positioned on the inner side, the right straight portion 41, and the right curved portion 42. The central curved portion 43, the left curved portion 44, and the left straight portion 45 are folded inward. The right convex portion 46 and the left convex portion 48 have the

seams

31D and 32D overlapped closely so that they are reinforced and are difficult to spread and difficult to cut. Is possible. The central concave portion 47 is slightly weaker in strength than the right convex portion 46 and the left convex portion 47 because the distance between the

seams

31E and 32E is separated, but the load is the right convex portion 46 and the left convex portion. Since it does not take 48, it can be used for a long time. Further, the right convex portion 46 and the left convex portion 48 have the right curved portion 42 and the left curved portion 44 folded inward, but since the

seams

31D and 32D overlap, the right curved portion 42 and the left curved portion 44. Therefore, the right curved portion 42 and the left curved portion 44 are less likely to become an obstacle when the filling is accommodated therein, and the filling can be accommodated without gaps in the vicinity of the

seams

31D and 32D.

Referring to FIGS. 17 and 18, the case where the article to be sewn is a leather seat of a car seat will be described. The seat back 100 includes a front sheet 101,

side sheets

102 and 102, and a back sheet 103, and is filled with a core material 105 and a pad 106 such as urethane foam. Since the front sheet 101 and the side sheet 102 are sewn in a curved manner, the front sheet 101 and the side sheet 102 are curved and sewn, and the

seams

107 and 108 are closely overlapped with each other, so that they are strong. Since the back sheet 103 and the side sheet 102 are sewn straight, they are straight stitches, and the

seams

107 and 108 are separated from each other. The front seat 101 is applied with a considerably strong force to support the movement of the driver, but since the periphery is reinforced with a seam overlap stitch, there is little possibility that the seam will stretch or break, and a safety aspect is secured. Furthermore, there is little possibility that part of the pad 106 is exposed and the appearance is impaired. In general, many bag-shaped sewing products are generally composed only of a curved line curve portion. If the sewing machine 1 performs curved sewing along the curved line curve portion, the bag-shaped sewing product is always in close contact. A pair of stitches can be obtained and strong sewing can be performed.

The two-needle sewing machine 61 shown in FIG. 19 will be described. In this two-needle sewing machine 61, sewing needles 71 and 72 are arranged on both sides in a direction substantially perpendicular to the feed direction T of the workpiece, and the sewing needle 72 arranged at a position (left side) away from the pedestal portion 65 is provided. The sewing needle 71 located rearward (the rear side in the feed direction T) and located near the pedestal 65 (right side) is located forward (the front side in the feed direction T), and the sewing needle 71 is sewn. It is provided on the feed side (front side) of the workpiece from the needle 72. As shown in FIG. 20, this two-needle sewing machine 61 is formed by

sewing needles

71 and 72 to form two seams substantially in parallel.

As shown in FIG. 19, the two-needle sewing machine 61 includes a bed portion 63 on which a sewing product such as cloth and leather is placed, and a pedestal standing upright from one (right side) side of the bed portion 63. The portion 65 and the arm portion 66 provided substantially in parallel with the bed portion 63 from the upper portion of the pedestal portion 65. A needle bar 67 that is reciprocated in the vertical direction by a drive motor (not shown) is provided at the tip portion (left portion) of the arm portion 66. Two

sewing needles

71 and 72 are attached to the needle bar 67. The bed portion 63 has two

horizontal hooks

73 and 74 that respectively hook the loops of the needle threads of the two

sewing needles

71 and 72, and a feed member 75 that feeds the workpiece in a direction substantially perpendicular to the bed portion 63. And have.

The sewing needles 71 and 72 are separated by about 3 mm or more from the relationship between the outer diameter of the sewing needle itself and the arrangement of the horizontal hook, and in order to make the width of the seam about 0.3 mm, The position of the sewing needle 72 is shifted. Therefore, although the interval between the sewing needles 71 and 72 is separated as described above, the interval between the sewing needles 71 and 72 in the direction substantially perpendicular to the sewing direction P1 (see FIG. 21) is narrow, and the width of the seam is narrowed. is doing.

The above-described two-needle sewing machine 61 intermittently feeds the workpieces to the front by the feeding member 75. However, the sewing needles 71 and 72 of the sewing needles 71 and 72 are prevented so that the sewing position of the workpieces is not shifted and sewing failure occurs. While confirming the sewing position visually, perform sewing while holding the sewing product with both hands. Such sewing is performed while checking the sewing position from the left side because the arm portion 66 exists on the right side with the sewing needles 71 and 72 as the center. The article to be sewn is not always linearly sewn, but may be sewn in a curved line according to the shape. When sewing in this curve, if the workpiece is rotated in the right direction (R direction) so as to approach the pedestal 65 with respect to the feed direction T of the feed member 75, the seam is formed due to the presence of the arm portion 66. May become difficult to see and may cause sewing defects. In addition, when the workpiece is rotated in the right direction (R direction), the workpiece comes into contact with the pedestal 65, so that it is difficult to perform sewing as intended by the operator. Therefore, the two-needle sewing machine 61 rotates the leftward direction (L direction) so as to separate the workpiece from the pedestal 65 with respect to the feed direction T of the feed member 75 when sewing in a curved manner.

As shown in FIG. 21, the two-needle sewing machine 61 sends a workpiece 30 in a sewing direction P1 substantially parallel to the feed direction T of the feed member 75, and thereby a normal stitch width is obtained by a pair of

sewing needles

71 and 72. A pair of

seams

81A and 82A provided with d1 are formed. As shown in FIG. 22, the two-needle sewing machine 61 rotates the workpiece 30 counterclockwise in the sewing direction P2 (inclination angle of about 5 degrees) away from the pedestal 65 with respect to the feed direction T of the feed member 75. By feeding, the distance between the sewing needles 71 and 72 in a direction substantially perpendicular to the sewing direction P2 is further increased, and a pair of stitches 81B having a stitch width d2 wider than the normal stitch width d1 by the pair of

sewing needles

71 and 72. , 82B.

As shown in FIG. 23, the two-needle sewing machine 61 sends the workpiece 30 by rotating it to the left in the P3 direction (inclination angle of about 10 degrees) away from the pedestal 5 with respect to the feed direction T of the feed member 75. As a result, the interval between the sewing needles 71 and 72 in a direction substantially perpendicular to the sewing direction P3 is further increased, and the pair of

sewing needles

71 and 72 has a pair of

seams

81C and 82C having a seam width d3 wider than the seam width d2. Form. As shown in FIG. 24, the two-needle sewing machine 61 sends the workpiece 30 by rotating it to the left in the P4 direction (inclination angle of about 15 degrees) away from the pedestal 5 with respect to the feed direction T of the feed member 75. As a result, the distance between the sewing needles 71 and 72 in a direction substantially perpendicular to the sewing direction P4 is further increased, and a pair of

seams

81D and 82D having a seam width d4 wider than the seam width d3 is provided by the pair of

sewing needles

71 and 72. Form. Thus, the stitch width of the two-needle sewing machine 61 is increased as the left rotation angle of the sewing object 30 is increased.

As shown in FIG. 25, the above-described bag-like sewing product 40 is sewn by the above-described two-needle sewing machine 61. By the two-needle sewing machine 61, sewing is performed substantially in parallel along the right straight portion 41 of the sewing product 40 in which the pair of

sheet members

40A, 40A are overlapped. Since the two-needle sewing machine 61 feeds the workpiece 40 in the P1 direction substantially parallel to the feed direction T of the feed member 75, a pair of

stitches

81A, 81A having a normal stitch width d1 is provided by the pair of

stitches

71, 72. 82A is formed. When sewing along the right curved portion 42, the two-needle sewing machine 61 sends the workpiece 40 while tilting it in a direction away from the pedestal portion 65 (left direction L) with respect to the feed direction T of the feed member 75. Therefore, the

stitches

81D and 82D are formed in a state where the stitch width d4 formed by the pair of

sewing needles

71 and 72 is wider than the normal stitch width d1.

When the two-needle sewing machine 61 performs sewing from the right curved portion 42 along the central curved portion 43, the direction in which the sewing product 40 approaches the pedestal 65 with respect to the feeding direction T of the feeding member 75 (right direction R ), The seam width d5 formed by the pair of

sewing needles

71 and 72 is narrowed to form the

seams

81E and 82E in an overlapped state. When the two-needle sewing machine 61 sews along the left curved portion 44 from the central curved portion 43, a direction (left direction L) in which the workpiece 40 is separated from the pedestal portion 65 with respect to the feeding direction T of the feeding member 75. ), The

stitches

sewing needles

71 and 72 is widened. When the two-needle sewing machine 61 performs sewing along the left straight line portion 45 from the left curved portion 44, the sewing product 40 is sent while being inclined in a direction approaching from the pedestal portion 65 with respect to the feed direction T of the feed member 75. Therefore, a pair of

seams

81A and 82A having a normal seam width d1 are formed by the pair of

sewing needles

71 and 72.

In the to-be-sewn product 40, the seam width d4 of the

seams

81D and 82D for sewing the peripheral edges of the

convex portions

46 and 48 is widened, and the seam width d5 of the

seams

81E and 82E for sewing the peripheral edges of the concave portion 47 overlaps. Become. In the case where the stuffing 40 is normally housed, the force applied to the

convex portions

46 and 48 is large, so that the

seams

81D and 82D are easily cut off due to insufficient strength due to the increased spacing between the

seams

81D and 82D. ing. Therefore, in the two-needle sewing machine 61, when the sewing product 40 having the

convex portions

46 and 48 is sewn, the width d4 of the

seams

81D and 82D for sewing the peripheral edges of the

convex portions

46 and 48 is widened and the strength is insufficient. Since the

seams

81D and 82D are easy to expand and cut when the padding is made in the

convex portions

46 and 48, the durability is poor. Thus, unlike the two-needle sewing machine 1, the two-needle sewing machine 61 can be understood to be not preferable because the width of the seam is widened and the strength is insufficient at the time of curve stitching. Therefore, in the two-needle sewing machine, it is desirable that the sewing needle disposed at a position distant from the pedestal portion is provided on the feed side of the sewing product from the sewing needle disposed at a position close to the pedestal portion.

The present invention can be used for a two-needle sewing machine that forms two stitches on a workpiece.

D1 stitch width, D2 stitch width, D3 stitch width, D4 stitch width, D5 stitch width, L left direction, P sewing direction (sewing direction), P1 sewing direction, P2 sewing direction, P3 sewing direction, P4 sewing direction, P5 sewing Direction, R right direction, T feed direction, 1 2-needle sewing machine, 2 sewing machine body, 3 bed part, 5 pedestal part, 6 arm part, 11 needle bar, 12 needle retaining member, 13 sewing needle, 14 sewing needle, 15 horizontal hook, 16 horizontal hook, 21 lower feed member, 30 sewing products, 31 stitches, 31A to 31E stitches, 32 stitches, 32A to 32E stitches, 40 sewing products, 40A seat, 40B seat, 41 right straight portion, 42 right curve part, 43 central curve part, 44 left curve part, 45 left straight part, 46 right convex part, 47 central concave part, 48 left convex part 61 2-needle sewing machine, 63 bed section, 65 pedestal section, 66 arm section, 67 needle bar, 71 sewing needle, 72 sewing needle, 73 horizontal hook, 74 horizontal hook, 75 feed member, 81 stitches, 81A to 81E stitches , 82 stitches, 82A to 82E stitches, 91 stitch needles, 92 stitch needles, 93 horizontal hooks, 94 horizontal hooks, 95 stitches, 96 stitches, 100 seat backs, 101 front seats, 102 side seats, 103 back seats, 105 cores 106 Pads 107 Seams 108 Seams

Claims

A bed portion on which the workpiece is placed;
A pedestal that stands up from one side of the bed,
An arm part provided substantially parallel to the bed part from the upper part of the pedestal part,
A needle bar provided at the tip of the arm and reciprocating in the vertical direction by a drive motor;
Two sewing needles attached to the needle bar;
Two horizontal hooks provided on the bed portion and hooking loops of needle threads of the two sewing needles;
A two-needle sewing machine having a feed member that feeds the sewing object in a direction substantially perpendicular to the bed portion;
Sewing needles are arranged on both sides in the direction substantially perpendicular to the feed direction of the workpiece, and the sewing needles arranged at positions away from the pedestal are closer to the workpiece than the sewing needles arranged near the pedestal. A two-needle sewing machine provided on the feed side.
A bed portion on which the workpiece is placed;
A pedestal that stands up from one side of the bed,
An arm part provided substantially parallel to the bed part from the upper part of the pedestal part,
A needle bar provided at the tip of the arm and reciprocating in the vertical direction by a drive motor;
Two sewing needles attached to the needle bar;
Two horizontal hooks provided on the bed portion and hooking loops of needle threads of the two sewing needles;
A feed member that sends the sewing object in a direction substantially perpendicular to the bed portion;
Sewing needles are arranged on both sides in the direction substantially perpendicular to the feed direction of the workpiece, and the sewing needles arranged at positions away from the pedestal are closer to the workpiece than the sewing needles arranged near the pedestal. A stitch forming method for a two-needle sewing machine provided on the feed side,
A pair of stitches having a normal stitch width are formed by a pair of sewing needles by feeding the workpiece in the feeding direction of the feeding member,
A pair of stitches having a seam width narrower than a normal seam width is formed by a pair of sewing needles by feeding the workpiece in a direction away from the pedestal portion with respect to the feed direction of the feed member. A method for forming a seam of a needle sewing machine.
A bed portion on which the workpiece is placed;
A pedestal that stands up from one side of the bed,
An arm part provided substantially parallel to the bed part from the upper part of the pedestal part,
A needle bar provided at the tip of the arm and reciprocating in the vertical direction by a drive motor;
Two sewing needles attached to the needle bar;
Two horizontal hooks provided on the bed portion and hooking loops of needle threads of the two sewing needles;
A feed member that sends the sewing object in a direction substantially perpendicular to the bed portion;
Sewing needles are arranged on both sides in the direction substantially perpendicular to the feed direction of the workpiece, and the sewing needles arranged at positions away from the pedestal are closer to the workpiece than the sewing needles arranged near the pedestal. A seam forming method for forming a seam on a peripheral edge of a sewing product having a convex portion by a two-needle sewing machine provided on a feeding side,
A pair of stitches having a normal stitch width are formed by a pair of sewing needles by feeding the workpiece in the feeding direction of the feeding member,
A pair of seams having a seam width narrower than a normal seam width is formed on the peripheral edge of the convex portion by a pair of sewing needles by feeding the workpiece in a direction away from the pedestal with respect to the feeding direction of the feeding member. A stitch forming method for a two-needle sewing machine characterized by